Species range shifts along multistressor mosaics in estuarine environments under future climate

Abstract

Range shifts are a key mechanism that species employ in response to climate change. Increasing global temperatures are driving species redistributions to cooler areas along three main spatial axes: increasing latitudes, altitudes and water depths. Climate‐mediated range shift theory focuses on temperature as the primary ecological driver, but global change alters other environmental factors as well, and these rarely work in isolation. Ecosystems are often characterized as mosaics of overlapping environmental stressors, resulting in temporal and spatial heterogeneity which differs between stable, low complexity mosaics (e.g. open ocean) and highly variable, highly complex mosaic environments (e.g. estuaries). We propose a multistressor mosaic of climate‐mediated species range shift across abiotic environmental gradients, typical for mobile species (e.g. fish) in variable coastal environments. We conceptualize how climate‐driven changes in salinity, temperature, dissolved oxygen and pH can drive redistribution of estuarine species in a future world. Non‐thermal drivers are a critical component of species range shifts and when not considered, underestimate the impact of global change on species populations and ecosystem services.